Esters of unsaturated acidbranched chain hexadiene polymer adducts



Patented June 5, 1951 ESTERS OF UN S AT URATED ACID- BRANCHED CHAINHEXADIEN E POLY- MER ADDUCTS Rupert 0. Morris, Berkeley, and John L. VanWinkle, San Lorenzo, Calif., assignors to Shell Development Company, SanFrancisco, Calif., a corporation of Delaware No Drawing. ApplicationApril 30, 1948, Serial No. 24,447

7 Claims.

This invention relates to novel ester compositions and it isparticularly directed to esters formed from adducts of variousunsaturated acids, or their ester-forming derivatives, and low molecularweight, cyclic polymers of branched chain hexadienes. This applicationis a continuation-impart of our co-pending application, Serial No.562,743, filed November 9, 1944, now Patent No. 2,463,769.

We have discovered that the esters of aliphatic, aromatic oraromatic-aliphatic alcohols or their ester-forming derivatives with theadducts formed by reactingalpha,beta-unsaturatedalpha,beta-dica1'b0xy1ic acids or theiresterforming derivatives with low molecular weight, cyclic polymers ofbranched chain hexadienes having in the molecule a straight chain offive carbon atoms, are particularly useful compounds possessing a widevariety of unusual and unexpected properties. For example, they arevaluable as plasticizers and tackifiers for elastomers of many kinds.Many of the esters, particularly those formed from unsaturated alcohols,have drying qualities which render them of outstanding value in coatingand impregnating compositions. Others, as those formed from polyhydricalcohols, are actually resinous in character, and can readily beconverted into high molecular weight polymer esters of the alkyd resintype. In addition to the foregoing properties, the various esters of thepresent invention are effective biocides and as such are valuableingredients in many insecticidal compositions.

The low molecular weight, cyclic polymers mentioned above are describedin detail in our copending application, Serial No. 562,051, filed No"vember 4, 1944, now Patent No. 2,429,582, as well as in the aforesaidparent application, Serial No. 562,743, and while reference is herebymade to said applications for a more complete disclosure on the score ofthe polymers, it may here be noted that one method of preparing the sameis to polymerize a branch chain, 1,3-hexadiene, having a straight chainof five carbon atoms, in the presence of sulfur dioxide and of eitheroxygen or an oxygen-yielding compound as catalyst. The polymerization ispreferably conducted at elevated temperatures, as 80 C. or above, andwith a mixture of hexadienes, as 2methyl-1,3-pentadiene and4-methyl-1,3-pentadiene. Preferred oxygenyielding catalysts for thispurpose are such peroxides as benzoyl peroxide, tertiary butylhydroperoxide, and iii-(tertiary butyl)-peroxide. An appreciable yieldof polymers may be obtained when only traces of peroxide are present.

Amounts as small as about 5 milli-equivalents of active oxygen per literof liquid hexadiene may be sufficient, though improved yields areobtained through the use of between 10 and 100 milliequivalents ofactive oxygen per liter of liquid hexadiene. The amount of sulfurdioxide employed may be varied over a wide range, though it is preferredto use at least one mol of this compound per mol of hexadiene reactant.

The low molecular weight polymers can also be produced by the thermalcracking of one or more di-methyl-sulfolenes. The latter compounds arecyclic mono-su1fones which are obtainable by reacting in the liquidphase one or more of the aforedesignated hexadienes (preferablyperoxidefree) with sulfur-dioxide, in the substantial absence ofmolecular oxygen and of oxygen-yielding substances, the reaction beingconducted at an elevated temperature which is below that at which themono-sulfones formed are decomposed. Temperatures in the neighborhood of100 C. are generally suitable. This method of preparing cyclicmono-sulfones is described in U. S. Patent No. 2,420,834, issued May 20,1947, and forms no part of the present invention. Typical, suitablecyclic mono-sulfones which may be employed in this manner are2,2-dimethyl-3sulfolene, 2,4dimethyl-3-sulfolene and2,5-dimethyl3-sulfolene. The term sulfolene is employed herein todesignate the unsaturated compound containing four carbon atoms and asulfur atom in a ring, said structure having a single olefinic linkagebetween two adjoining carbon atoms, with the sulfur atom having twooxygen atoms attached thereto and with the remaining free bonds of thenuclear carbon atoms being attached to hydrogen atoms. The term isnormally prefixed by either 2- or 3- so as to indicate the position ofthe double bond. This compound has also been termedthiacyclopentene-1,l-dioxide. In accordance with well recognizednomenclature practice, the term 2- or 3-sul1folene may also form a partof the name of particular compounds wherein one or more of the hydrogenatoms attached to the carbon-sulfur nucleus of the cyclic sulfonecompound are substituted by a corresponding number of other functionalgroups in the numbered position of the ring indicated in the case ofeach particular compound.

The crude product obtained either from the designated monomerichexadienes by polymerization in the presence of sulfur dioxide and ofoxygen or oxygen-yielding substances, or by the cracking ofdimethylsulfolenes, is a yellow viscous liquid consisting principally ofa mixture of low molecular weight polymers of the hexadienes.

It may contain a very small amount (a trace) of sulfur-containingimpurities and of unreacted hexadienes. These impurities can be removedand a stable, more uniform product obtained simply by maintaining thepolymers at an elevated temperature, desirably 200 to 225 C., preferablyunder atmospheric or reduced pressures. Heating for 2 to 4 hours isordinarily satisfactory, although shorter or longer periods may beemployed. The thus purified mixture of polymers gives a negative testfor sulfur and sulfur-containing compounds. The mixture of polymers maybe separated into several fractions by distillation, preferably underreduced pressures, or by other methods such as solvent extraction, etc.Fractions boiling below about 380 C. under atmospheric pressures consistprincipally of dimers, trimers and tetramers (which contain cyclicstructures), of the 'hexadienes. Approximately 52% of the polymersubstance boils above about 490 C. under atmospheric pressures andconsists essentially of a mixture of polymers the average, or apparentmolecular weight of which is substantially equal to that of a seven-unitpolymer '(having a polymerization degree of about seven) containing inthe molecule the structure This higher molecular weight fraction isobtained as'a yellow, very viscous, sticky liquid, soluble inhydrocarbons. For most purposes the mixture of polymers need not befractionated but may be employed as such. If desired, however, anyfraction or combination of fractions may be used in place of the wholemixture.

The aforesaid hexadiene polymers may be reacted with substantially anyalpha,beta-unsaturated-alpha,beta-dicarboxylic acid or ester-formingderivative thereof in order to produce the polymer-acid adducts fromwhich the ester comi pounds of this invention are prepared. Relativelylow molecular weight unsaturated acids having not more than about 8carbon atoms in the molecule are preferred because of their greaterreactivity. However, where the speed of reaction with the polymers isnot of primary importance higher acids may be employed. It has beenfound that the most useful adducts are produced from acid reactants ortheir derivatives having at least salts, esters and other ester-formingderivatives of these and like compounds may be employed. Mixtures of twoor more such unsaturated acid reactants (which term includes the acids,anhydrides, salts, esters and other ester-forming derivatives heredescribed) may also be employed.

For technical and economic reasons maleic anhydride is the preferredreactant.

The amount of alpha,beta-unsaturated-alpha, beta-dicarboxylic acid whichmay be reacted with the low molecular weight cyclic hexadiene polymersmay be varied over a wide range. The properties of the polymers aresignificantly altered and valuable products are produced where ratios assmall as aboutone mol of alpha,beta-unsaturated-alpha,beta-dicarboxylicacid are employed for each about carbon atoms of polymer, i. e., foreach 20 hexadiene units combined in the polymer. Such products haveimproved body, faster drying and/ or high oil solubility. Ratios as highas about one molecule of dicarboxylic acid to each hexadiene unit may beemployed. The reaction may be carried out in a simple manner by merelyintimately mixing the cyclic polymer and thealpha,beta-unsaturated-alpha,beta dicarboxylic acid and heating themixture under atmospheric pressures. If desired, one or both of thereactants may be added portion-wise to the reaction mixture at intervalsduring the reaction,ralthough this procedure is ordinarily notnecessary. Under most conditions no appreciable reaction occurs attemperatures below about 0., although such lower temperatures may besuitable in some cases. Temperatures of between about 175 C. and about200 C. are preferred. Higher temperatures ordinarily cause discolorationof the product, particularly where oxygen is present during thereaction. However, where light color is not of primary consideration,temperatures as high as about 300 C. may be employed. The reaction maybe carried out in a continuous or discontinuous manner. Atmosphericpressures are ordinarily satisfactory, although superatmosphericpressures may be employed and reduced pressures may be advantageousunder some conditions. atmospheric pressures reflux conditions may beprovided. Gaseous oxygen may be present, although products of somewhatimproved color may be obtained by excluding oxygen, conveniently byproviding the reaction mixture with a blanket of an oxygen-free fluid,e. g., an oxygen-free gas such as nitrogen, carbon dioxide, etc. Thetime required for the reaction is dependent upon the particularreactants involved, the reaction tem' perature, etc. With the morereactive acid reactants such as maleic anhydride, the reaction may besubstantially complete in an hour or less. In other cases much longerheating times may be required. The preferred procedure in all caseswhere the initial reaction mixture consists essentially only of cyclicpolymers and acid anhydride reactants is to continue heating until amixture is obtained which on cooling remains in one liquid phase.

Following the reaction, the addition products of the cyclic polymerswith the acid reactants may be separated from any other ingredients ofthe reaction mixture and further purified by any suitable known orspecial methods. Unreacted acid reactants may usually be removed bydistillation, preferably under reduced pressures. Alternatively,unreacted acids and anhydrides may be removed by washing with hot water.Further purification may be effected by solvent extraction and the like.

The above described polymer-acid addition products employed in formingthe esters of this invention vary in viscosity from readily mobileliquids to hard, brittle solids, depending principally upon the natureand the proportions of the reactants. In the case of the reaction ofmaleic anhydride with an unfractionated mix- Where the reaction iscarried out under ture of low molecular weight cyclic hexadiene polymerssuch as may be obtained by the cracking of a dimethyl-sulfolene or bythe reaction of a suitable hexadiene under the; designated conditions,the influence of the relative proportions of anhydride and polymer inthe adduct upon the properties thereof is shown in the following table:

isopropyl, normal butyl, isobutyl, secondary butyl, tertiary butyl,normal pentyl, isopentyl, secondary pentyl, hexyl, normal octyl,isoctyl, normal decyl, isodecyl, dodecyl, tetradecyl, cetyl, stearyl,trimethyl octadecyl, allyl, methallyl, crotyl, ethyl vinyl carbinyl,butenyl, pentenyl, hexenyl, propargyl, geranyl, oleyl, phenyl, naphthyl,anthyl, tolyl, xylyl, secondary butyl-naph- Water-white mineral oilconsisting principally of saturated aliphatic hydrocarbonsRepresentative analyses show that the above addition products correspondto the formula [(CeI-Im) 1/C4H2O311c, wherein 1/ represents the ratio ofhexadiene monomer units to each mol of maleic anhydride in the adduct,and so is that number which, when multiplied by y, gives as product thenumber of hexadiene monomer units in the molecule. Knowing the molecularweight (M) of the polymer (or its average molecular weight), and thenumber of hexadiene monomer units remaining the same in both polymer andadduct molecules (averaging about 7.5 with unfractionated polymermixtures), then as is equal where 82 is the molecular weight ofhexadiene. Conversion of the polymer-anhydride addition products to theacid form may be effected readily by heating a solution of the anhydrideproduct in dilute aqueous alkali for a short time, followed byacidification and recovery of the precipitated acid product. Othermethods will be obvious to those skilled in the art.

The ester compounds of the present invention are produced by knownesterification procedures employing as'reactants the polymer-acidadducts of the type described above and an appropriate alcohol orequivalent ester-forming compound. Alcohols are the preferred class ofcompounds for supplying the desired radical necessary to the formationof an ester with the adduct and may be employed when said adductincorporates either acids, acid anhydrides, acid chlorides, or evenesters the desired ester here being formed by the mechanism of esterinterchange). However, other compounds can be employed instead ofalcohols to form the desired esters, alkyl halides, for example,reacting with the adducts formed from the polymer described above and anacid salt to form the desired ester. Those conditions which have beenfound conducive to esterification reactions in general may be employedhere, as will be discussed more fully in subsequent portions of thisdescription.

The radical which is associated with the adduct} to form the ester ofthis invention may be of either the aliphatic, aromatic oraromaticaliphatic type and can be derived, as stated above, from analcohol or any ester-forming derivative thereof. Examples of suitableesterifying radicals are methyl, ethyl, propyl,

thyl, dipropyl-naphthyl, benzoyl, naphthyl-butyl, phenethyl, vinylphenyl, crotonyl naphthyl, methallyl-phenyl, triallyl-naphthyl,naphthylallyl, Z-phenyl-ethenyl, phenyl vinyl carbinyl, cyclopentyl,ethyl-cyclohexyl, tributyl-cyclohexyl, cyclopentenyl, cyclo-hexenyl andvinyl cyclohexenyl. These radicals may be substituted with otherelements or groups, as the halides, which do not interfere with thedesired esterification reaction.

Esters in which some or all of the carboxyl or equivalent groups in thepolymer adduct are esterified with alkyl, aryl, or aralkyl groups, asethyl, phenyl, or ethylphenyl, are particularly valuable as biocides,though they are also useful as plasticizing compositions, and as organicintermediates.

Other useful ester compounds of this invention are these wherein theadducts are combined with one or more of various unsaturated alcoholradicals. Polymerizable esters of this type include those in which theadducts are esterified with allyl-type alcohols (compounds having adouble bond of aliphatic character between two carbon atoms one of whichis attached to a saturated carbon atom which in turn is attached to analcoholic hydroxyl group) as represented by allyl alcohol, methallylalcohol, chloroallyl alcohol, or crotyl alcohol; with propargyl-typealcohols (compounds having a triple bond of aliphatic character betweentwo carbon atoms one of which is attached to a saturated carbon atomwhich in turn is attached to an alcoholic hydroxyl group) as representedby propargyl alcohol, etc; or with vinyl-type alcohols (compounds havinga double bond of aliphatic character between two carbon atoms one ofwhich is attached to an alcoholic hydroxyl group) as represented byvinyl alcohol, propen-l-ol-2, etc. Many of these unsaturated esters areuseful as plasticizers and tackifiers for elastomers generally, butparticularly for natural and synthetic rubbers. Others have dryingproperties which render them valuable ingredients in coating andimpregnating compositions. Further, these unsaturated esters are capableof being readily polymerized into resinous polymers of high molecularweight, this polymerization reaction generally going forward on theapplication of heat and optionally in the presenceof a catalyst.Preferred catalysts for this purpose are peroxides as, for example,benzoyl peroxide, acetyl peroxide, benzoyl acetyl peroxide, tertiarybutyl perbenzoate, tertiary butyl hydroperoxide, di-(tertiary butyl)peroxide, peracetic acid, or the like. Such high molecular weight estersof this invention, besides having many of the useful qualities of thelow molecular weight esters, are themselves useful plastic compositions.

I The polymer-containing adducts may also be reacted with polyhydricalcohols to produce compounds known as polyesters. polyhydric alcoholswhich are suitable for this purpose are glycol, diethylene glycol,triethyleneglycol, propylene glycol, butylene glycol, glycerol,diglycerol, pentaglycerol, pentaerythritol, polypentaerythritols, andpolyhydric alcohols produced (actually or theoretically) by thepolymerization of unsaturated aliphatic alcohols, as allyl alcohol, orby the hydrolysis of a suitable polyhydric alcohol derivative. Thus,polyvinyl alcohol and polyallyl alcohol may be produced from thecorresponding esters, acetals and the like. Instead of, or in additionto, polyhydric alcohols there may be used ester-forming derivativesthereof such as the corresponding epoxides, e. g., glycidol,epichlorohydrin, and the like.

In forming polyesters, it has been found that with adducts wherein theproportion of acid or anhydride to polymer is unusually high, gellingoccurs before the esterification process is complete. compounds of thisinvention it is preferable to make use of adducts containing no morethan about 7% by weight of combined dicarboxylic acid, the range of from4% to 7% being preferred. In other respects, no limitation need beplaced on the ratio of either the components of the various reactants orupon the reactants themselves. Preferably, however, the esters of thepresent invention are produced under such circumstances that no excessof the alcohol or equivalent esterforming compound remains in the finalester product. The foregoing polyesters, in addition to having valuableplasticizing and insecticidal properties, are particularly well adaptedfor conversion into high molecular weight polyesters of the type knownas alkyd resins. Alkyd resins can be produced from low molecular weightpolyesters by heating the latter, preferably in the presence of, acatalyst such as a suitable metal oxide,.e. g., zinc, magnesium, orcalcium oxide, or a finely divided metal, e. g., zinc or iron; asuitable liquid catalyst, e. g., furfural, or its derivatives andequivalents (methyl furfural, phenol methyl furfural, furfur-actone), ora phenolformaldehyde condensation product. The resin can be produced inthe fusible stage and, if desired, be subsequently infusibilized as bythe further application of heat. The alkyd resins of this invention areof great value in the manufacture of plastic coating compositions andthe like, and many of them are rubbery in character.

The proportions in which the adduct and alcoholreactants are combined toform the esters of the present invention are not critical, though it ispreferred that the reaction be conducted under such circumstances thatthe resulting product contains the maximum possible number of esterlinkages. This result may best be obtained by conducting the reaction inthe presence of an excess of the alcohol (of its equivalentester-forming compound), with any excess of alcohol being removed at theend of the reaction.

The esterification reaction may be executed in the presence or absenceof a catalyst. Suitable promoters or catalysts which may be used toaccelerate the rate of esterification are the strong Representative anynumber of ways.

Accordingly, in producing the polyester 8 mineral acids such as H2604,H3PO4, HzSaOv, HPOs, H01, HBr, H4P2O7, HC103, H0104, HNO3, and the like.Mineral acid substances of the type Of SO zClz, SOC12, SOBlz, N02, N203,NOCl, PCh, P015, and the like may also be employed. Inorganicacid-acting salts such as ZnSOa, ZnClz, ZnBrz, FeCla, A1C13, COClz,NlClz, FeflSOUs, Alz(SO4)3, NaHSOr, NaI-I2PO4, and the like may also 'beused. Organic acid-acting compounds such as benzene sulfonic acid,p-toluene sulfonic acid, and their homologues and analogues, dialkyl andacid alkyl sulfates, alkylated phosphoric acid and sulfonic acids, etc.,may also be employed alone or in combination with any of theabovementioned or other suitable substances as catalysts for theesterification reaction.

The esterification reaction may be executed in One method ofesterification comprises heating the adduct in contact with the alcohol,preferably in a suitable reaction vessel equipped with agitating means.The reactants may be introduced into the reactor sepa-' rately, or theymay be mixed prior to their introduction thereinto. In many cases it isdesirable toeifect the esterification' by heating the reactants at aboutthe boiling temperature of the reaction mixture and at approximatelyatmospheric pressure, though in some instances the use ofsuper-atmospheric pressures and/or higher tem peratures may be found tospeed up the reaction.

The rate of esterification may be increased and the occurrence ofundesirable side reactions decreased by operating in such a manner thatthe water formed as the result of the esterification is removed from thereaction mixture substantially as soon as it is formed. In someinstances this removal may be efiected by allowing the process to takeplace at a temperature sufficiently high to permit distillation of thewater from the reaction mixture, though a preferred method is to add anazeotrope-forming agent such as benzene or other inert hydrocarbon.

The following examples illustrate the manner 7 in which the presentinvention finds preferre embodiment: r

Example I Hexadiene polymer was produced by placing 904 parts of2,4-dimethyl-3-sulfolene (prepared,

for example, by a practice of the method set forth in detail in eitherof Examples VI or- VII of the aforementioned U. S. Patent No. 2,420,834)in a glass reaction kettle under. a water-cooled reflux condenser whichwas open to the atmos;- phere and the kettle was heated slowly. When thekettle temperature reached 87 C. decomposition of the sulfone wasevident. The temperature was thereafter regulated to provide for thedecomposition of the sulfone at such a rate that the sulfur dioxideevolved did not sweep any of the reactant or other products out of V thekettle. Evolved sulfur dioxide was discarded. At the end of three hours,when the decomposition was substantially complete, the temperature hadreached 151 C. 1 Heating was continued for an additional four hours, thetempera ture being raised gradually to 191 C. The resi: due, 494 parts,was a crude mixture of low mo: lecular weight polymers, containing0.006% of sulfur. The polymer was stabilized and purie fied by heatingin an open vessel exposed to the air at 200-225 C. for four hours. No'sulfur could be detected in the purified polymer. In order to obtain apolymer-anhydride adduct suitable for conversion into the ester form, a

mixture of 250 parts of the hexadiene polymer, produced as describedabove, and 299 parts of maleic anhydride were heated under a blanket ofnitrogen with constant stirring for 2 hours imder atmospheric pressures.On cooling, the reaction mixture separated into two phases. The mixturewas then heated for another 4 to 5 hours at 180 to 185 C., followingwhich the reaction mixture on cooling consisted of only one phase. Thereaction mixture was washed with hot water to remove unreacted maleicanhydride and then dried by heating at a relatively low temperatureunder reduced pressure. A yield of 387 parts of product having thecomposition was obtained. The product was soluble in dilute alkali andslightly solube in light, saturated mineral oil. I

The foregoing addition product was then esterified with ethyl alcohol inthe following manner: To a glass kettle attached to a separating headwas charged a mixture of 156 parts of the addition product, 244 parts ofbenzene, 258 parts of ethyl alcohol, and 2 parts of para-toluenesulfonic acid. The mixture was refluxed for 76 hours during which time19 parts of water were removed. The mixture was then washed with waterand excess ethyl alcohol and benzene were removed under vacuum. Theproduct was a viscous liquid having the approximate composition[(Cal-I102.(CHCOOCzHshh. It was found to have particular value as aplasticizer.

Example II A maleic anhydride-polymer adduct was produced in the mannerdescribed above in Example I except that here the proportion of polymerto anhydride was such that the resulting addition product had theapproximate composition [(C6Hl0)3C4H203]z. A mixture of 110 parts of thelatter compound with 34 parts of diethylene glycol was then placed in aglass reaction kettle and stirred at atmospheric pressure in thepresence of air for one hour and 5 minutes, the temperature beinggradually increased from an initial value of about 55 C. at the start ofthe reaction to about 256 C. at its finish. The reaction product at 256C. was a soft, dark solid having thread-forming properties and theproperties of alkyd resins generally. Approximately 10% of the reactionproduct was soluble in a mixture of equal parts by volume of toluene andamyl acetate.

Example III An alkyd resin was produced in accordance with the procedureoutlined in Example II except that in this case glycerol was employedinstead of diethylene glycol, and the final reaction temperature was 248C. The resulting product, when cooled to room temperature, was amoderately hard solid which was more than 10% soluble in a mixture ofequal parts by volume of toluene and amyl acetate.

Example IV An unsaturated ester composition is produced by reacting theadduct of Example I with methallyl alcohol, the reactants being employedin the ratio of one part of the adduct to 2.5 parts of the alcohol. Theresulting ester has the approximate composition 10 and proves useful asa component of various paints. The product is polymerized into aninsoluble material on further heating in the presence of benzoylperoxide.

Molecular weights referred to herein were determined according to themethod described by B. J. Mair in the Bureau of Standards Journal ofResearch, 14, 345 (1935). The term unsaturated as used herein refers tocarbon-to-carbon unsaturation of aliphatic character.

We claim as our invention:

1. An ester of a compound selected from the group consisting of thelower oxy-substituted alkyl alcohols and the lower oXy-substitutedalkenyl alcohols with an addition product made up of a compound selectedfrom the group consisting ofalpha,beta-unsaturated-alpha,betadicarboxylic aliphatic acids and theanhydrides, salts and esters of said acids in combination with a lowmolecular weight unsaturated, cyclic polymer of a branch-chain1,3-hexadiene having a straight chain of 5 carbon atoms in the molecule.

2. An ester of an alpha,beta-unsaturated lower alkenyl alcohol with anaddition product made up of a compound selected from the groupconsisting of alpha,beta-unsaturated-alpha,betadicarboxylic aliphaticacids and the anhydrides, salts and esters of said acids in combinationwith a low molecular weight unsaturated cyclic polymer of a branch-chain1,3-hexadiene having a straight chain of 5 carbon atoms in the molecule.

3. The compound of claim 2 where the ester is polymerized to form a highmolecular weight polymer.

4. An ester of a lower alkyl polyhydric alcohol with an addition productmade up of a compound selected from the group consisting of alpha,betaunsaturated alpha,beta dicarboxylic aliphatic acids and the anhydrides,salts and esters of said acids in combination with a low molecularweight, unsaturated cyclic polymer of a branch-chain 1,3-hexadienehaving a straight chain of 5 carbon atoms in the molecule.

5. An ester of ethyl alcohol with an addition product formed betweenmaleic anhydride and a low molecular weight, unsaturated cyclic polymerof a branched-chain 1,3-hexadiene having a straight chain of 5 carbonatoms in the molecule.

6. An ester of diethylene glycol with an addition product formed betweenmaleic anhydride and a low molecular weight, unsaturated cyclic polymerof a branched-chain 1,3-hexadiene having a straight chain of 5 carbonatoms in the molecule.

7. An ester of glycerol with an addition product formed between maleicanhydride and a low molecular weight, unsaturated cyclic polymer of abranched-chain 1,3-hexadiene having a straight chain of 5 carbon atomsin the molecule.

RUPERT C. MORRIS. JOHN L. VAN WINKLE.

REFERENCES CITED Name Date Morris May 3, 1949 Number

1. AN ESTER OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF THELOWER OXY-SUBSTITUTED ALKYL ALCOHOLS AND THE LOWER OXY-SUBSTITUTEDALKENYL ALCOHOLS WITH AN ADDITION PRODUCT MADE UP OF A COMPOUND SELECTEDFROM THE GROUP CONSISTTING OF ALPHA-BETA-UNSATURATED-ALPHABETADICARBOXYLIC ALIPHATIC ACIDS AND THE ANHYDRIDES. SALTS AND ESTERS OFSAID ACIDS IN COMBINATION WITH A LOW MOLECULAR WEIGHT UNSATURATED,CYCLIC POLYMER OF A BRANCH-CHAIN 1, 3-HEXADIENE HAVING A STRAIGHT CHAINOF 5 CARBON ATOMS IN THE MOLECULE.